The present invention relates generally to conveyors for conveying cafeteria trays, waiter/waitress trays, pallets, dish boxes, dish racks or like articles and relates more particularly to a modular conveyor system for mechanized foodservice installations such as cafeterias for the removal of trays loaded with soiled dishes, glasses, trash, garbage, silverware (flatware) and the like from a dining area for delivery to a dish and tray washing and storage area, said conveyor system being reversible to return clean items to their point of use.
Although the present conveyor system and particularly the drive arrangement thereof will have utility in other fields, it was developed primarily for foodservice applications and specifically to provide an inexpensive and versatile modular conveyor system for conveying loaded trays in either direction and at variable speeds. Accordingly, the following discussion and description thereof will be directed primarily to the conveying of trays of the type widely used for foodservice; however, it will be apparent that other types of trays, boxes, pallets or other rigid objects could also be conveyed by the present system.
The commercially available tray conveying systems for use in foodservice are extremely expensive, largely due to their complex construction which requires individual one of a kind engineering/custom fabrication and involved installation steps. Most of the types presently sold comprise belts driven over rollers or are of the slat or pallet type wherein a chain drive system moves parallel slats or pallets on which the trays are disposed along the conveyor path. These systems due to the frictional drag of the belts or pallets require substantial amounts of power and accordingly must utilize large, heavy and expensive drive components.
Conveyors for foodservice use are subject to the interrupting influence of dishes, silverware and food particles which inadvertently tumble from the trays and tend to become lodged in operating elements of the conveyor mechanism. The slat or pallet type conveyor is particularly subject to difficulties of this type, particularly with silverware which tends to fall between and break up the slats, requiring continual, expensive replacement and repairs.
Since foodservice conveyors generally must move trays from a dining area to a remote dish, silverware and tray cleaning and storage area, the conveyor may pass through several rooms or work areas, in the course of which it must often make turns, and/or ascend or descend to most efficiently utilize the space available. In some instances, the conveyors actually ascend or descend to different floors of a building, which with presently available conveyor systems requires custom engineering and custom fabrication, resulting in a very expensive and space consuming installation.
The complexity of available foodservice conveyors further makes them difficult to clean as well as to maintain. Their complexity results in high maintenance costs and a breakdown of one part can shut the entire conveyor down for substantial periods until the parts and highly skilled labor are available to effect the necessary repairs. Furthermore, the typical commercially available slat type conveyor, although capable of traversing curves, is not reversible and its function is accordingly limited to delivery of trays in one direction only. Although belt type conveyors may be reversed, they are incapable of traversing curves.
Many of the problems associated with conventional conveyors flow from the provision in such conveyor constructions of a belt or a surface comprised of slats or pallets moving the entire length of the conveyo on which the loaded trays ride, plus the return of empty belts or slats the full length of the conveyor. Even in the absence of any trays on such a conveyor, a substantial amount of energy is expended, to overcome friction, in moving the large inertial mass of the conveying platform along the length and return of the conveyor. It is furthermore difficult to stop the progress of a tray on a conveyor of this type since the entire surface on which the tray is resting is in continual movement, making unloading of the trays a difficult operation. Because of friction and spillage, the conventional conveyors require dishwasher machine type belts or pallet washing devices to keep the belts or pallets clean. These washing devices require extensive hot and cold water, drains, and detergent use, with excess detergent being used to help reduce friction; they are thus costly and require constant surveillance.
Because commercially available conveyor systems employ both belt and pallet type drive neither of which can radius upward or downward, the joining of a level section to a slanted section results in a sharp abrupt angle, which creates tray jarring action as the tray passes over such abrupt joint. This tray jarring causes spillage of the tray contents together with excessive noise, vibration, and the telescoping of trays one into the other.